The present invention relates to electronic program guides (EPG) for digital television systems. In particular, the present invention relates to the transmission of electronic program guide data in hypertext markup language (HTML) in an MPEG digital television system.
The Federal Communications Commission (FCC) recently approved a digital television format based on the Moving Picture Experts Group 2 (MPEG-2), as a standard for the transmission of digital TV in the United States. The MPEG-2 digital television format provides improved picture and sound quality. In addition, the MPEG-2 digital television format permits the digital TV signal to carry ancillary digital data, which facilitates additional services based on the ability of the digital TV signal format to efficiently transport digital data.
Electronic program guide (EPG) systems are known. A typical electronic program guide system, embodied in a settop box such as a satellite receiver or cable TV decoder (or in the TV receiver itself), receives a database of TV programming information (basic EPG data) encoded in a digital data format, broadcast over a satellite, cable or terrestrial channel. For example, one type of EPG system broadcasts a digital database of EPG data in the vertical blanking interval of an analog television signal. The EPG database is received at the settop, decoded locally and stored in local memory.
Responsive to viewer requests, the locally stored EPG database in local memory is then formatted from basic EPG data into a program guide EPG display form that can be displayed on the TV screen. The simplest EPG display is a TV programming grid, organized as channel versus time, similar to the typical programming grid appearing in a printed paper television guide. The locally stored basic EPG data is typically searched and sorted responsive to each viewer request, and the resulting guide information is generated and displayed on the TV screen. For example, the viewer may request a list of all sports events, or a list of all movies broadcast on that day, or on a future day. Responsive to each request, the processor in the settop searches, sorts and formats the locally stored EPG database into a customized EPG display.
Prior art EPG systems typically require a large local memory to store the EPG database, and a fast local processor to search, sort and display the EPG data.
In comparison with printed TV program guides, electronic program guides offer larger capacity, electronic searching, last minute updates, and other features such as searching and sorting that are not practical with printed paper guides. More recently, on line television guides via the Internet provide an alternative to on-screen television guides and printed paper guides. However, Internet services and on-line TV guides are designed for a two-way network model, as compared to broadcast TV and associated on-screen TV guides, which are designed for a one way network model.
Despite the competition from paper television guides and personal computer on-line television guides, the broadcast TV screen is the best place to view program guide information. It is more convenient for viewers to search for TV related information on the TV itself, rather than in some other place, such as a paper magazine or a home office personal computer. The EPG feature has proven to be attractive to viewers, and is one of the most important data applications for TV networks. The present invention provides an EPG solution for a one way broadcast digital TV network.
In accordance with the present invention an electronic program guide is embodied in a rotating data carousel of HTML pages formatted to be transported in the data packets of an MPEG-2 data stream. First, at the headend of the broadcast system, the basic EPG data is formatted into HTML and related data formats as the page description language for the presentation of EPG content.
Hypertext Markup Language and the related standards that comprise most Web content (i.e., image formats, style sheets, etc.) provide a thorough framework for describing the presentation of multimedia content. An HTML-based EPG leverages the huge base of tools, media, and know-how that has been developed for the Web. Prior art on-screen EPG implementations on cable TV settop boxes and satellite receivers typically use some sort of proprietary storage and display format. In the present invention, an on-screen EPG is implemented using standard Internet based Web HTML format.
Next, in accordance with the present invention, the EPG in HTML format is partitioned into MPEG-2 data packets for transport over an MPEG-2 digital television network, while retaining the HTML format. The EPG in HTML format is transmitted as a rotating data carousel of HTML pages, along with control maps that allow the viewer to navigate among the HTML Web pages of the EPG. In such manner, the normally two-way network model of the World Wide Web is adapted for use in a one-way MPEG-2-based digital TV network by broadcasting a rotating carousel comprising an ensemble of EPG Web pages plus control maps for navigation, in an MPEG-2 digital TV signal. Since the MPEG-2 settop box uses the control maps to navigate among a rotating carousel of HTML Web pages, the need for local memory to store basic EPG data is reduced. Also, since the MPEG-2 settop receives previously composed EPG display pages in HTML format, the need for local processing power to search and sort the basic EPG data, and to generate proprietary on-screen TV displays is reduced. Settop boxes tend to require Internet service in addition to EPG service. The present EPG is much more efficient in terms of processing power and cost compared with running an Internet service in parallel to a proprietary EPG service.
Television settop boxes, like most consumer electronic devices, are cost-sensitive. Manufactures make great efforts to reduce the cost of settop boxes. As a result of cost reduction measures, TV settop boxes have less local memory and a relatively slower microprocessor as compared to the memory size and processing speed of personal computers. In terms of memory and speed, settop TV boxes are resource-deprived. The present invention is adapted for use with such resource-deprived settop boxes to process and display EPG Web pages with satisfactory performance.